Sulfur Dioxide Complexes of Main-Group Elements: from SO₂⁰ to SO₂^– and SO₂^2– upon Coordination to Aluminum and Silicon Difluorides

Abstract

The AlF 2 (O 2 S) and SiF 2 (O 2 S) complexes with bidentately coordinated sulfur dioxide ligands were prepared via the reactions of aluminum and silicon atoms with SO 2 F 2 under UV−vis irradiation in cryogenic matrixes. The products were identified by infrared spectroscopy as well as DFT frequency calculations, and nonplanar C 2v structures with the SO 2 ligand bound to Al/Si via two oxygen atoms were established. In spite of the similarity in geometric structures, the electronic structures of AlF 2 (O 2 S) and SiF 2 (O 2 S) are completely different. The longer S−O bond length and the lower O−S−O stretching vibrational frequencies of SiF 2 (O 2 S) in comparison to those of AlF 2 (O 2 S) indicate that SiF 2 (O 2 S) possesses a singlet SO 2 2− -like ligand while the SO 2 ligand is better described as SO 2 − in AlF 2 (O 2 S), which is further confirmed by bonding and population analysis. Linear correlations were established between the experimental O−S−O stretching frequencies and calculated S−O bond lengths of SO 2 , AlF 2 (O 2 S), and SiF 2 (O 2 S), suggesting that the S−O bond is gradually activated when SO 2 is coordinated to AlF 2 and SiF 2 .

A sulfur monoxide complex of platinum fluoride with a positively charged ligand

“…Although the exact reason for this abnormal shift is unclear, it has been observed for the metal fluoride stretching bands of some metal sulfur monoxide and dioxide complexes. 22,44 For the most intense S–O stretching band predicted at 1245.7 cm −1 , the 32 S/ 34 S frequency ratio of 1.0105 and 16 O/ 18 O frequency ratio of 1.0381 agree well with the experimental values of 1.0104 and 1.0373, respectively, for the observed band at 1205.4 cm −1 . The infrared intensity of the last band at 480.2 cm −1 is too low to be observed.…”

Preparation of Group 3 Metal Sulfur Monoxide Complexes via Oxidation of Metal Atoms using SOF2 in Cryogenic Matrixes

“…This could be due to the coupling between vibrational modes, and such abnormal isotopic frequency shift has been observed in the sulfur dioxide complex of aluminum difluoride. [17] We also optimized the structure of ScF 2 (η 2 -SO) using the M06 functional, and the vibrational frequencies are close to those obtained at the B3LYP level with a better SÀ O stretching vibrational frequency (Table S3). Note that the isotopic ratios for all the bands including the symmetric FÀ ScÀ F stretching band are also similar with both functionals.…”

“…[11][12][13][14] It has been recently demonstrated that sulfuryl fluoride (SO 2 F 2 ) can serve as a precursor for the convenient synthesis of metal-sulfur dioxide complexes when it reacts with metal atoms in cryogenic matrixes. [15][16][17] In particular, sulfur monoxide complexes were obtained in some cases as long as there are enough valence electrons from the metal center to support one SO and one oxo ligand as well as two fluoro ligands. [18,19] The reactions of molybdenum and tungsten atoms with SO 2 F 2 in solid matrixes gave rise to side-on OMoF 2 (η 2 -SO) and OWF 2 (η 2 -SO), which are considered as peroxo-like metal complexes, (OMoF 2 ) 2 + (SO) 2À and (OWF 2 ) 2 + (SO) 2À .…”

Deoxygenation of chalcogen oxides EO2 (E = S, Se) with phospha-Wittig reagents

“…4 Flue gas desulfurization requires effective interactions of a certain material with SO 2 and several strategies have been developed to sequester SO 2 at ambient conditions. From the perspective of a main-group chemist, SO 2 binding [5][6][7][8][9][10][11][12][13][14][15] and activation, [16][17][18][19][20][21] conversion and/or reduction, [22][23][24][25][26][27][28] but also sorption [29][30][31][32][33] have been realized.…”